content: // Protocol Buffers - Google's data interchange format
  // Copyright 2008 Google Inc.  All rights reserved.
  // https://developers.google.com/protocol-buffers/
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  package com.google.protobuf;
  
  import static com.google.protobuf.IsValidUtf8TestUtil.DIRECT_NIO_FACTORY;
  import static com.google.protobuf.IsValidUtf8TestUtil.EXPECTED_ONE_BYTE_ROUNDTRIPPABLE_COUNT;
  import static com.google.protobuf.IsValidUtf8TestUtil.EXPECTED_THREE_BYTE_ROUNDTRIPPABLE_COUNT;
  import static com.google.protobuf.IsValidUtf8TestUtil.HEAP_NIO_FACTORY;
  import static com.google.protobuf.IsValidUtf8TestUtil.LITERAL_FACTORY;
  import static com.google.protobuf.IsValidUtf8TestUtil.testBytes;
  
  import com.google.protobuf.IsValidUtf8TestUtil.ByteStringFactory;
  import com.google.protobuf.IsValidUtf8TestUtil.Shard;
  
  import junit.framework.TestCase;
  
  /**
   * Tests cases for {@link ByteString#isValidUtf8()}. This includes three
   * brute force tests that actually test every permutation of one byte, two byte,
   * and three byte sequences to ensure that the method produces the right result
   * for every possible byte encoding where "right" means it's consistent with
   * java's UTF-8 string encoding/decoding such that the method returns true for
   * any sequence that will round trip when converted to a String and then back to
   * bytes and will return false for any sequence that will not round trip.
   * See also {@link IsValidUtf8FourByteTest}. It also includes some
   * other more targeted tests.
   *
   * @author jonp@google.com (Jon Perlow)
   * @author martinrb@google.com (Martin Buchholz)
   */
  public class IsValidUtf8Test extends TestCase {
    /**
     * Tests that round tripping of all two byte permutations work.
     */
    public void testIsValidUtf8_1Byte() {
      testBytes(LITERAL_FACTORY, 1, EXPECTED_ONE_BYTE_ROUNDTRIPPABLE_COUNT);
      testBytes(HEAP_NIO_FACTORY, 1, EXPECTED_ONE_BYTE_ROUNDTRIPPABLE_COUNT);
      testBytes(DIRECT_NIO_FACTORY, 1, EXPECTED_ONE_BYTE_ROUNDTRIPPABLE_COUNT);
    }
  
    /**
     * Tests that round tripping of all two byte permutations work.
     */
    public void testIsValidUtf8_2Bytes() {
      testBytes(LITERAL_FACTORY, 2, IsValidUtf8TestUtil.EXPECTED_TWO_BYTE_ROUNDTRIPPABLE_COUNT);
      testBytes(HEAP_NIO_FACTORY, 2, IsValidUtf8TestUtil.EXPECTED_TWO_BYTE_ROUNDTRIPPABLE_COUNT);
      testBytes(DIRECT_NIO_FACTORY, 2, IsValidUtf8TestUtil.EXPECTED_TWO_BYTE_ROUNDTRIPPABLE_COUNT);
    }
  
    /**
     * Tests that round tripping of all three byte permutations work.
     */
    public void testIsValidUtf8_3Bytes() {
      // Travis' OOM killer doesn't like this test
      if (System.getenv("TRAVIS") == null) {
        testBytes(LITERAL_FACTORY, 3, EXPECTED_THREE_BYTE_ROUNDTRIPPABLE_COUNT);
        testBytes(HEAP_NIO_FACTORY, 3, EXPECTED_THREE_BYTE_ROUNDTRIPPABLE_COUNT);
        testBytes(DIRECT_NIO_FACTORY, 3, EXPECTED_THREE_BYTE_ROUNDTRIPPABLE_COUNT);
      }
    }
  
    /**
     * Tests that round tripping of a sample of four byte permutations work.
     * All permutations are prohibitively expensive to test for automated runs;
     * {@link IsValidUtf8FourByteTest} is used for full coverage. This method
     * tests specific four-byte cases.
     */
    public void testIsValidUtf8_4BytesSamples() {
      // Valid 4 byte.
      assertValidUtf8(0xF0, 0xA4, 0xAD, 0xA2);
  
      // Bad trailing bytes
      assertInvalidUtf8(0xF0, 0xA4, 0xAD, 0x7F);
      assertInvalidUtf8(0xF0, 0xA4, 0xAD, 0xC0);
  
      // Special cases for byte2
      assertInvalidUtf8(0xF0, 0x8F, 0xAD, 0xA2);
      assertInvalidUtf8(0xF4, 0x90, 0xAD, 0xA2);
    }
  
    /**
     * Tests some hard-coded test cases.
     */
    public void testSomeSequences() {
      // Empty
      assertTrue(asBytes("").isValidUtf8());
  
      // One-byte characters, including control characters
      assertTrue(asBytes("\u0000abc\u007f").isValidUtf8());
  
      // Two-byte characters
      assertTrue(asBytes("\u00a2\u00a2").isValidUtf8());
  
      // Three-byte characters
      assertTrue(asBytes("\u020ac\u020ac").isValidUtf8());
  
      // Four-byte characters
      assertTrue(asBytes("\u024B62\u024B62").isValidUtf8());
  
      // Mixed string
      assertTrue(asBytes("a\u020ac\u00a2b\\u024B62u020acc\u00a2de\u024B62").isValidUtf8());
  
      // Not a valid string
      assertInvalidUtf8(-1, 0, -1, 0);
    }
  
    private byte[] toByteArray(int... bytes) {
      byte[] realBytes = new byte[bytes.length];
      for (int i = 0; i < bytes.length; i++) {
        realBytes[i] = (byte) bytes[i];
      }
      return realBytes;
    }
  
    private void assertValidUtf8(ByteStringFactory factory, int[] bytes, boolean not) {
      byte[] realBytes = toByteArray(bytes);
      assertTrue(not ^ Utf8.isValidUtf8(realBytes));
      assertTrue(not ^ Utf8.isValidUtf8(realBytes, 0, bytes.length));
      ByteString leaf = factory.newByteString(realBytes);
      ByteString sub = leaf.substring(0, bytes.length);
      assertTrue(not ^ leaf.isValidUtf8());
      assertTrue(not ^ sub.isValidUtf8());
      ByteString[] ropes = {
          RopeByteString.newInstanceForTest(ByteString.EMPTY, leaf),
          RopeByteString.newInstanceForTest(ByteString.EMPTY, sub),
          RopeByteString.newInstanceForTest(leaf, ByteString.EMPTY),
          RopeByteString.newInstanceForTest(sub, ByteString.EMPTY),
          RopeByteString.newInstanceForTest(sub, leaf)};
      for (ByteString rope : ropes) {
        assertTrue(not ^ rope.isValidUtf8());
      }
    }
  
    private void assertValidUtf8(int... bytes) {
      assertValidUtf8(LITERAL_FACTORY, bytes, false);
      assertValidUtf8(HEAP_NIO_FACTORY, bytes, false);
      assertValidUtf8(DIRECT_NIO_FACTORY, bytes, false);
    }
  
    private void assertInvalidUtf8(int... bytes) {
      assertValidUtf8(LITERAL_FACTORY, bytes, true);
      assertValidUtf8(HEAP_NIO_FACTORY, bytes, true);
      assertValidUtf8(DIRECT_NIO_FACTORY, bytes, true);
    }
  
    private static ByteString asBytes(String s) {
      return ByteString.copyFromUtf8(s);
    }
  
    public void testShardsHaveExpectedRoundTrippables() {
      // A sanity check.
      int actual = 0;
      for (Shard shard : IsValidUtf8TestUtil.FOUR_BYTE_SHARDS) {
        actual += shard.expected;
      }
      assertEquals(IsValidUtf8TestUtil.EXPECTED_FOUR_BYTE_ROUNDTRIPPABLE_COUNT, actual);
    }
  }
  